Interface Attribute

This interface represents an attribute associated with a named object.

In a directory, named objects can have associated with them
attributes. The Attribute interface represents an attribute associated
with a named object. An attribute contains 0 or more, possibly null, values.
The attribute values can be ordered or unordered (see isOrdered()).
If the values are unordered, no duplicates are allowed.
If the values are ordered, duplicates are allowed.

The content and representation of an attribute and its values is defined by
the attribute's schema. The schema contains information
about the attribute's syntax and other properties about the attribute.
See getAttributeDefinition() and
getAttributeSyntaxDefinition()
for details regarding how to get schema information about an attribute
if the underlying directory service supports schemas.

Equality of two attributes is determined by the implementation class.
A simple implementation can use Object.equals() to determine equality
of attribute values, while a more sophisticated implementation might
make use of schema information to determine equality.
Similarly, one implementation might provide a static storage
structure which simply returns the values passed to its
constructor, while another implementation might define get() and
getAll().
to get the values dynamically from the directory.

Note that updates to Attribute (such as adding or removing a
value) do not affect the corresponding representation of the attribute
in the directory. Updates to the directory can only be effected
using operations in the DirContext interface.

serialVersionUID

Method Detail

getAll

Retrieves an enumeration of the attribute's values.
The behaviour of this enumeration is unspecified
if the attribute's values are added, changed,
or removed while the enumeration is in progress.
If the attribute values are ordered, the enumeration's items
will be ordered.

Returns:

A non-null enumeration of the attribute's values.
Each element of the enumeration is a possibly null Object. The object's
class is the class of the attribute value. The element is null
if the attribute's value is null.
If the attribute has zero values, an empty enumeration
is returned.

Throws:

NamingException - If a naming exception was encountered while retrieving
the values.

get

Retrieves one of this attribute's values.
If the attribute has more than one value and is unordered, any one of
the values is returned.
If the attribute has more than one value and is ordered, the
first value is returned.

Returns:

A possibly null object representing one of
the attribute's value. It is null if the attribute's value
is null.

Throws:

NamingException - If a naming exception was encountered while retrieving
the value.

add

Adds a new value to the attribute.
If the attribute values are unordered and
attrVal is already in the attribute, this method does nothing.
If the attribute values are ordered, attrVal is added to the end of
the list of attribute values.

Equality is determined by the implementation, which may use
Object.equals() or schema information to determine equality.

Parameters:

attrVal - The new possibly null value to add. If null, null
is added as an attribute value.

Returns:

true if a value was added; false otherwise.

remove

Removes a specified value from the attribute.
If attrval is not in the attribute, this method does nothing.
If the attribute values are ordered, the first occurrence of
attrVal is removed and attribute values at indices greater
than the removed
value are shifted up towards the head of the list (and their indices
decremented by one).

Equality is determined by the implementation, which may use
Object.equals() or schema information to determine equality.

Parameters:

attrval - The possibly null value to remove from this attribute.
If null, remove the attribute value that is null.

Returns:

true if the value was removed; false otherwise.

clear

void clear()

Removes all values from this attribute.

getAttributeSyntaxDefinition

Retrieves the syntax definition associated with the attribute.
An attribute's syntax definition specifies the format
of the attribute's value(s). Note that this is different from
the attribute value's representation as a Java object. Syntax
definition refers to the directory's notion of syntax.

For example, even though a value might be
a Java String object, its directory syntax might be "Printable String"
or "Telephone Number". Or a value might be a byte array, and its
directory syntax is "JPEG" or "Certificate".
For example, if this attribute's syntax is "JPEG",
this method would return the syntax definition for "JPEG".

The information that you can retrieve from a syntax definition
is directory-dependent.

If an implementation does not support schemas, it should throw
OperationNotSupportedException. If an implementation does support
schemas, it should define this method to return the appropriate
information.

Returns:

The attribute's syntax definition. Null if the implementation
supports schemas but this particular attribute does not have
any schema information.

getAttributeDefinition

Retrieves the attribute's schema definition.
An attribute's schema definition contains information
such as whether the attribute is multivalued or single-valued,
the matching rules to use when comparing the attribute's values.
The information that you can retrieve from an attribute definition
is directory-dependent.

If an implementation does not support schemas, it should throw
OperationNotSupportedException. If an implementation does support
schemas, it should define this method to return the appropriate
information.

Returns:

This attribute's schema definition. Null if the implementation
supports schemas but this particular attribute does not have
any schema information.

clone

Makes a copy of the attribute.
The copy contains the same attribute values as the original attribute:
the attribute values are not themselves cloned.
Changes to the copy will not affect the original and vice versa.

Returns:

A non-null copy of the attribute.

isOrdered

boolean isOrdered()

Determines whether this attribute's values are ordered.
If an attribute's values are ordered, duplicate values are allowed.
If an attribute's values are unordered, they are presented
in any order and there are no duplicate values.

get

Retrieves the attribute value from the ordered list of attribute values.
This method returns the value at the ix index of the list of
attribute values.
If the attribute values are unordered,
this method returns the value that happens to be at that index.

Parameters:

ix - The index of the value in the ordered list of attribute values.
0 <= ix < size().

Returns:

The possibly null attribute value at index ix;
null if the attribute value is null.

Throws:

NamingException - If a naming exception was encountered while
retrieving the value.

remove

Removes an attribute value from the ordered list of attribute values.
This method removes the value at the ix index of the list of
attribute values.
If the attribute values are unordered,
this method removes the value that happens to be at that index.
Values located at indices greater than ix are shifted up towards
the front of the list (and their indices decremented by one).

Parameters:

ix - The index of the value to remove.
0 <= ix < size().

Returns:

The possibly null attribute value at index ix that was removed;
null if the attribute value is null.

add

Adds an attribute value to the ordered list of attribute values.
This method adds attrVal to the list of attribute values at
index ix.
Values located at indices at or greater than ix are
shifted down towards the end of the list (and their indices incremented
by one).
If the attribute values are unordered and already have attrVal,
IllegalStateException is thrown.

Parameters:

ix - The index in the ordered list of attribute values to add the new value.
0 <= ix <= size().

attrVal - The possibly null attribute value to add; if null, null is
the value added.

set

Sets an attribute value in the ordered list of attribute values.
This method sets the value at the ix index of the list of
attribute values to be attrVal. The old value is removed.
If the attribute values are unordered,
this method sets the value that happens to be at that index
to attrVal, unless attrVal is already one of the values.
In that case, IllegalStateException is thrown.

Parameters:

ix - The index of the value in the ordered list of attribute values.
0 <= ix < size().

attrVal - The possibly null attribute value to use.
If null, 'null' replaces the old value.

Returns:

The possibly null attribute value at index ix that was replaced.
Null if the attribute value was null.